Various types of cracks in building walls

In this construction article, you will get detail information on the different types of cracks generally found in building walls.

Types of Cracks in Walls:
Type # 1. Horizontal Crack at the Junction of Roof Slab and Masonry Wall Support

i. Crack in load bearing wall: Because of the following factors, horizontal crack at the roof level of the uppermost floor, underneath the slab, may happen :-

a. The slab experiences alternative expansion and contraction because of fluctuation in ambient temperature.
b. Insufficient protective cover to get rid of heat on the roof.
c. Arrangement of large space of the slab in the interior of the room that leads to extreme deflection and containing insufficient vertical load over the support to withstand lift up of the slab at the support and movement of the slab is restricted on one side.

Thermal expansion of the slab inducting cracks may result in bending caused by thermal gradient in the slab. Under this situation, the cracks are visible from the outside, on top level of the slab; whereas it is visible at the bottom level of the slab from inside.

To take precaution, construction of the support of the R.C.C. on the masonry wall should be done as per the image given below.

Arrangement of L-beam with minimal reinforcement, combined with the slab would form inflexibility against deflection.

ii. Crack in non-load bearing wall — Cladding and cross-walls of framed structure:

For framed structure roof slab, beams, and columns progress together which lead to diagonal cracks in walls normally parallel to the movement and horizontal cracks are situated under the beams. Stretch of movement in a framed structure is reasonably less as columns due to their stiffness and capability to resist bending stresses. So, the movement is controlled to some extent.

Both in load-bearing and framed structures, arrangement of sufficient or preventive cover on the roof is very crucial to get rid of cracks in walls.

Type # 2. Vertical Cracks at Junction of R.C.C. Column and Wall Masonry:

The cracks are noticeable few months once the construction is completed. This happens because of differential strain among R.C.C. and masonry as well as elastic deformation, shrinkage and creep in R.C.C. column.

For precaution, arrange butterfly ties at the junctions.

To get more information on other types of cracks, go through the following construction article yourarticlelibrary.com

Various types of cracks in building walls

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Published By
Arka Roy
http://www.constructioncost.co
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Some useful tips to reduce the cost of your home

In recent times, the construction cost of a home is significantly increased due to rise in the land costs, construction & material costs as well as labor charges.

Given below, some useful tips to reduce the cost of home construction :-

The construction cost of a home is segregated into following five categories :-

1. Land Cost: Cost of owning a land parcel for House construction 2. Design Costs: It comprises of architectural, structural and MEP design of the building 3. Laisoning Costs: It involves fees for government approvals like government land survey, plan approval etc. 4. Material Procurement Costs: It contains buying various types of materials like cement, steel, sand, aggregate, bricks, blocks, tiles and other finishing materials 5. Labour Costs: It comprises of the manpower costs for construction of RCC structure, brick work, plastering, other finishing works and exterior expansion (Like compound wall, hardscaping and landscaping)

Saving In Land Cost: Select the proper plot for construction: The level of the plot is a crucial factor throughout construction. If the level of the plot is much lower as compared to the road level on the front, then the greater quantity of filling material will be needed and entire construction cost will be raised. Therefore, opt for a land parcel that is neither extremely high or low with regards to the level of the road.

Check development regulations: Survey area that has the feasibility to construction building in near future. It is presently accessible at low cost. Verify FSI of the area; more FSI signifies less total cost of owning a home. If FSI is less, then it is required to purchase more land to develop same area of construction.

As for instance: If you make plan to purchase a 1000 sqft plot area and searching at 2 localities. You local municipality or DC (Development Control) provides FSI for each area on the basis of several factors. Therefore, if a plot contains 2 FSI, it is possible to build up a 2000 sqft building whereas in a plot with 1.5 FSI, 1500 sqft are can be built up.

It should also be remembered FSI regulations will be altered in due course, so you have to select the exact plot as per your present and future requirements.

Saving In Construction Material Procurement:

Cement: It is recommended to purchase local/regional branded cement. Use only local branded cements like Chettinad cement, Penna cement, Maha cement etc. since they have standard quality and are available at better prices.

The proper grade of cement should be utilized to make best use of the cement consumption. OPC cement is normally slightly costlier with reference to PPC cement. OPC cement is best suited for RCC structural work (like foundations, columns, roof and beams) and PPC cement is suggested for non-structural works (Like Plastering, Tiling etc.,). It will save significant costs as well as improves the quality of construction by lessening of cracks (because of less heat of hydration).

To make best use of the cement consumption in structural concrete, the fly ash can be mixed with caution (15 to 25% as part replacement to cement) with OPC 53 cement. It will reduce the costs but the longevity will be increased (as degree of permeability will be low).

Bricks And Blocks:

1. It is recommended to purchase local bricks which are easily accessible. As for instance the first class red clay brick and fly-ash brick in your locality. Select a brick with low cost. Both fly ash bricks and red clay bricks have good strength.

2. In case of building up a structure containing over 3 floors, then AAC blocks should be used in place of bricks. Although AAC blocks alias concrete blocks are more expensive as compared to the bricks, but their weight is light. It will reduce the steel consumption per unit constructed, since dead load is decreased to one-third. Since AAC blocks contain low thermal conductivity, they can allow you to save electricity costs for cooling your rooms.

Plastering: Opt for Neeru (lime) Finish for internal plastering.

Doors And Windows:

3. Refrain from using wooden door frames. Rather use RCC door frames which will save up to 30% of the cost for Door framing.
4. Opt for PVC doors for Bathrooms and other wet areas like dry balcony etc.,
5. Opt for laminated flush door or block board for door opening except for the main door. It will reduce the cost of door work by 25%.
Flooring: 6. Utilize cement mosaic tiles to decrease the cost of flooring works. Choose size that leads to less wastages.
7. Opt for locally accessible granite for Kitchen platform and stair case steps. Utilize cut/waste piece of tiles in steps riser.

Grill And Railings: Utilize painted MS section for staircase railing and grills

Electrical Material: Use local make switches and sockets but always select for branded wires for House wiring.

Light Fitting: Choose light fittings which are inexpensive initially but also save up on the electricity charges and maintenance costs in the future.

Avoid False Ceiling: Though false ceiling performs as good insulation but is very costly. Select for a simple POP finish to the roof.

Paints: Utilize Semi-acrylic paint for internal and external walls which can save upon the cost.

Plumbing CP Fixtures & Sanitary: The cost of sanitary and CP fixtures differ based on the type and quality of products which are utilized in the building and its cost reduction depends on the individual preference. Select economical local/regional brands. Plumbing and Sanitary fixture will be easily substituted anytime devoid of demolishing in future. So, these can be substituted later with your selected fixtures and cost will be reduced.

To get more details go through www.happho.com

Some useful tips to reduce the cost of your home

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Published By
Arka Roy
http://www.constructioncost.co
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Design of concrete structures – An exclusive e-book for civil engineering students

DESIGN OF CONCRETE STRUCTURES is an exclusive e-book for construction professionals. The book contains 612 pages.

The book primarily focuses on various processes which are required to design the concrete structures with adherence to IS 456-2000 (Plain and Reinforced Concrete—Indian Standard Code of Practice, 4th revision, Bureau of Indian Standards).

It provides special attention to the limit state method in order to demonstrate the allowable limits for the safety and serviceability requirements of structures.

The book sheds light on yield line analysis for slabs as well as the working stress method and how it is applied for creating the design of reinforced concrete tension members; theory of redistribution of moments, the earthquake proof design of structures.

The book is well supported with several solved problems along with step-by-step calculations. The application of SP-16 (Design Aids for Reinforced Concrete to IS: 456–1978) is also briefly discussed in resolving the issues.

The books contain the following exclusive features :-

1. Instructional Objectives provided at the starting of the chapter point out to vital concepts.
2. Summary at the end of the chapter is provided to facilitate student revise key points.
3. Sixty-nine solved illustrative examples demonstrate step-by-step calculations.

4. Chapter-end exercises are provided to evaluate student’s understanding of the concepts.
5. There are forty tests to allow the students to measure their skills for actual exams.
6. This wide-ranging text is very effective for undergraduate students of civil engineering and architecture as well as professional engineers.

Go through the following video tutorial to learn how WTF aluminum form is set up in high rise structure.

To download the book, click on the following link phindia.com

Design of concrete structures – An exclusive e-book for civil engineering students

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Published By
Arka Roy
http://www.constructioncost.co
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How to set up formwork in high rise structures

Aluminum formwork is very effective for both high and low-rise concrete construction projects. Aluminum formwork technology can significantly minimize the labor costs as well as makes the project cycles shorter.

WTF aluminum formwork is a highly recognized construction system for building up cast in place concrete structures. WTF offers aluminum formwork for reinforced concrete construction ranging from single and multi-story buildings and facilitates the walls and slab to be positioned monolithically in the similar operation. It enhances efficiency and builds up an extremely robust structure with superb concrete finish.

The WTF Aluminum Formwork System is excellent since it builds all of the components in the structure along with walls, floor slabs, columns, beams, stairs, window details, balconies, and different decorative features with adherence to the architect’s design.

WTF aluminum formwork technology is a complete system that can be employed for simple column, beam and slab constructions through to more complicated features like curved structures, staircases, and all architectural features.

Go through the following video tutorial to learn how WTF aluminum form is set up in high rise structure.

Video Source: Civil Engineering

How to set up formwork in high rise structures

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Published By
Arka Roy
http://www.constructioncost.co
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Some useful tip on placing of Reinforcement

Reinforcement should be perfectly arranged and sufficiently supported prior to placing of concrete as well as safeguarded against displacement within allowable tolerances which are given below.

The tolerances, given below, should be maintained while placing reinforcement unless otherwise mentioned by the engineer:

(a) Tolerances for depth d, and minimum concrete cover in flexural members, walls and compression members should be as follow :-

Tolerances for Placing Reinforcement

Tolerance for d – Tolerance for Minimum Concrete Cover

d ≤ 200 mm ±10 mm –10 mm
d > 200 mm ±13 mm –13 mm

(b) Regardless the provision of (a) above, tolerance for the clear distance to formed soffits should be minus 6 mm and tolerance for cover should not be in excess of minus 1/3 the minimum concrete cover stated in the design drawings or specifications.

(c) Tolerance for longitudinal location of bends and ends of reinforcement should be ± 50 mm, excluding at discontinuous ends of brackets and corbels, where tolerance should be ± 13 mm and at discontinuous ends of other members, where tolerance should be ±25 mm. The tolerance for concrete cover should also be used in discontinuous ends of members.

Welded wire reinforcement (with wire size not more than MW30 or MD30) applied in slabs not over and above 3 m in span should be allowed to be curved from a point adjacent to the top of slab over the support to a point near the bottom of slab at midspan, in case such reinforcement is either continuous over, or securely anchored at support.

Welding of crossing bars should not be allowed for assembly of reinforcement unless the concerned engineer approve.

Some useful tip on placing of Reinforcement

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Published By
Arka Roy
http://www.constructioncost.co
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Benefits and drawbacks of air entrained concrete

Air entrained concrete is formed by providing little air bubbles into concrete is called air entrainment. Air entrainment is performed with the use of air entraining Portland cement or air entraining agents like admixture.

The amount of air in such concrete is normally kept among four to seven percent of the volume of concrete.

Various types of methods like galvanometric method, volumetric method and pressure method are used to work out the concrete volume. The air bubbles mitigate internal pressure on the concrete by arranging chambers for water to be extended at the time of getting freezed.

Method – Air in concrete in integrated in the following ways:

 By utilizing gas forming materials like aluminium powder, zinc powder and hydrogen peroxide.  With the application of surface active agents that minimizes surface tension. These may contain natural wood resins and their soaps, animal or vegetable fats or oils, alkali salts of sulfonated or sulphated organic compounds.  With the help of cement dispersing agents.

Benefits – Given below, some of the benefits of air entrained concrete:

1. Workability of concrete is raised significantly.
2. The impact of freezing and thawing is reduced with air entraining agent.
3. Bleeding, segregation and laitance in concrete are decreased.

4. Entrained air makes the sulphate repelling strength of concrete.
5. Minimizes the chance of shrinkage and crack development in the concrete surface.

Drawbacks – Given below, some of the drawbacks of air entrained concrete:

a. The strength of concrete is reduced.
b. Air entraining agent can raise the porosity of concrete and consequently the unit weight is decreased.
c. Air-entrainment in concrete should not be performed if the site control is not superior because the air entrained in a concrete differs with the alteration in sand grading, errors in proportioning and workability of the mix and temperatures.

Benefits and drawbacks of air entrained concrete

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Published By
Arka Roy
http://www.constructioncost.co
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Brief explanation of Cement Hydration Process

This construction video tutorial provides useful information for the students who will appear in SSC and JE exam. The video is presented by the renowned civil engineer Mr. Parag Pal and it sheds light on cement hydration process. Mr. Pal briefly explains the term rate of heat liberation throughout pouring of concrete.

Before delve into the video, first learn the definition of hydration :-

When series of unchangeable exothermic chemical reactions occur among cement and water, it is defined as hydration.

With existence of water, the silicates and aluminates develop the products of hydration which in due course form a rigid (solid) and hard mass i.e. the hydrated cement paste.

Production of hydration products ultimately results in stiffening (loss of adaptability), setting (consolidation), hardening (strength gain).

Hydration process is ceaseless still the heat and moisture exist in the cement.

To gather sufficient knowledge on the fundamentals of hydration is very important for the following reason :-

Assure the strength and longevity of concrete.

Identify and alleviate the stresses to resist cracking.

Recognize the significance of superior curing and construction practices.

Go through the following video tutorial to learn the detail hydration process.

Brief explanation of Cement Hydration Process

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Published By
Arka Roy
http://www.constructioncost.co
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Brief overview of rise and fall table in land surveying

This construction video tutorial is very useful for land surveyor. The tutorial sheds light on the rise and fall table in land surveying. Get some useful tricks to resolve the rise and fall table.

Rise and fall method is applied to resolve the levelling to detect the variation in elevation and elevation of points..

By resolving this table, it is possible to work out the reduced level of each point captured at staff rod with leveling machine. In order to work out the reduced level of an individual point, it is necessary to compute the rise and fall of points. After that, for reduced level, the following formula is applied :-

new R.L = old R.L – Fall
new R.L = old R.L + Rise

The table contains various heads like number, B.S (back sight), I.S (inter sight), F.S (fore sight), Rise, Fall, R.L (reduced level) and remarks.

B.S – Back sight (BS) is the abbreviation for “back sight reading”. It means the first staff reading captured by the surveyor as soon as the levelling instrument is arranged and levelled. B.S is normally captured on the point of known reduced level as on the benchmark or a change point. The normally applied datum is mean sea level.

Fore sight (FS) is the abbreviation for “fore sight reading”. It means the last staff reading captured prior to modify the instrument to the other position. It refers to the staff reading captured on point whose RL is to be ascertained. This sight is treated as negative and assumed from Height of Instrument to find out RL of the point.

Reduced Level (RL) in surveying stands for equating elevations of survey points relating to a common assumed datum. It refers to a vertical distance among survey point and selected datum plane. Therefore, it is taken as the base elevation that is applied as reference to consider heights or depths of other important places.

To get more detailed information, watch the following video tutorial.

Brief overview of rise and fall table in land surveying

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Published By
Arka Roy
http://www.constructioncost.co
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Details of chain surveying – Benefits and Drawbacks

Chain surveying is the sort of surveying in which only linear measurements are selected in the jobsite.

This type of surveying is undertaken for surveys of small span to specify the boundaries of plot of land to detect the existing features on them.

Chain surveying is the simplest form of survey in which surveying area is segregated into a number of triangles and the sides of different triangles are calculated directly in the field through a chain or a tape and no angular measurements are chosen. Chain is most recommended for initial survey process.

Chains stands for the measuring devices which are applied in surveying. These are produced with the 100 links of 4mm galvanized mild steel wire. These links are attached with 3 circular or oval wire rings. These rings make the chains flexible.

The chain comprised of several small segments to manage or study the measurements.

At the ends chain contains brass handle with swivel joint to simplify the process for rolling or unrolling the chain devoid of twisting and knots.

At each 10th link is arranged with a total of one teeth, 20th link with a total of two teeth and so on till 40th link. With these arrangements, the reading of measurements can be taken efficiently.

At the center of the chain, there is a circular talley used for easy reading.

Chain surveying devices: 1. Chain, 2. Tape, 3. Arrows, 4. Ranging Rods, 5. Offset Staff, 6. Optical Square

Types of Chains utilized in Surveying – The chains are categorized as follow depending on the length of the chain:

Metric chains, Steel band or Band chain, Gunter’s chain or surveyor’s chain, Engineer’s chain, Revenue chain

Benefits of chains :-

a. The chains can be read easily and instantly
b. They can resist wear and tear
c. They can be repaired in the jobsite without any difficulty

d. There is no requirement to adjust measuring tape
e. This type of survey work is very effective for a small plain ground.
f. It needs simple instruments.
g. Plotting of maps is very simple and trouble-free.

Drawbacks of chain:

a. They are heavy and take long time to open or fold.
b. They turn to be longer or shorter because of repeated use.
c. If measurement is done in suspension the chain sags greatly.
d. Error in measurement may occur because of temperature, sagging and marking.
e. Requires more manpower to complete the layout.

This type of surveying is recommended for undulation land where chaining operation is tiresome and prone to errors. This method should not be undertaken for a crowded city containing a huge numbers of buildings and obstacles since it cannot be separated into well-conditioned triangles. As for instance route surveying.

For conducting the survey work of a road, irrigation canal, railways, water and sewer lines, tunneling etc., this method is not suitable at all.

Details of chain surveying - Benefits and Drawbacks

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Published By
Arka Roy
http://www.constructioncost.co
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Fast Form Bracket System offers complete slab wall & sheet pile capping formwork Solution

Fast-Form provides complete solution for different types of pile cap, slab, base, beam, wall and sheet pile capping beam formwork whether they come in straight or radius, single or double sided.

This system can efficiently bolts together to facilitate casting kickers, plinths, hang bolts as well as monolithic bund walls etc.

There are 2 types of bases to pin directly to hard-core and ground by means of road pins, or bolt with re-usable concrete bolts to slabs and blinding concrete or even fasten them to decking with wood screws.

This system can be used without any difficulty. Just attach the brackets in a line and plumb up, screw on your ply from behind and pour your concrete.

Brackets are angled forward or back to make adjustment with sloping and battered pours along with irregular ground, thus making them much more compliant as compared to timber or panel systems.

The brackets are generated from superior grade galvanized steel to get rid of rust and they have longevity of 25 years plus. They are strong and do not get damaged. They can be also used underwater. Different sizes are available which range from 150 / 200 / 400 / 600 / 800 / 1200 & 1800mm high.

KEY BENEFITS:

• SAFETY: Access, handrails & toe boards, lightweight system that can be easily set up manually instantly and securely.
• SPEED: No need of de-nailing, lightweight and user-friendly system much faster as compared to conventional process and very simple to use with low labour skill levels.

• COST: It is very cost-effective as compared to timber with reduced labour and plant costs.
• ENVIROMENTAL: Little or no timber wastage and 100% completely recyclable materials which significantly minimize carbon emission deliveries.
• BETTER FINISH: Fair face finishes are obtained easily. The brackets are available with an F4 finish. So, fewer remedial works are required. Ply is fixed from behind systems, so, there is no marks on face of the concrete and any grade ply can be utilized as per your requirement.

To get more information, visit www.fastformsystems.com

Fast Form Bracket System offers complete slab wall & sheet pile capping formwork Solution

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Published By
Arka Roy
http://www.constructioncost.co
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